Stefan Monnier <monnier@iro.umontreal.ca> writes:

> Could you clarify which part of the picture make you think so?
> [ Also, does (featurep 'dash) return nil or t before you perform that
>   completion?  ]

I do:

• emacs -Q
• Eval:
    (progn
      (setq completions-format 'vertical)
      (package-initialize)
      (featurep 'dash))
  which returns nil
• 'C-h v TAB' and see this: